Optical distance-measuring instrument.



P. DUBBNHORST. OPTICAL DISTANCE MBASURING INSTRUMENT.

APPLIOATIQN FILED APR. 7, 1908. y

Patented Nov. 30, 1909.

' images withoutl lateral reversion in which the axis of the ocularsubstantially coincides UNITED erna-nsw rappeur onirica FRIEDRICHDUBENHOST, OI-STEGLITZ, NEAR BERLIN, GERMANY, ASSIGNOR TO THE FIRM 0FOPTISCI-IE ANSTALT C; P. GOERZ'AKTIENGESELLSCHAFT, 0F FRIEDENAU,

NEAR BERLIN, GERMANY.

OPTICAL-DIS'IJANCEMEASURING INSTRUMENT. i

Specification of Letters Patent..

Application 'Ied April 7,' 1908. Serial No. 425,639.

v' To all whom it may con-cern:

Be it known -that I, FRIEDRICH ADUBEN- IIoRs'r, a citizen of the vGermanEmpire, and resident lof 8a Irlubertusstrlasse, Steglitz, near Berlin,lGermany,- engineer, have invented certain new and useful Improvements-in Optical-Distance -Measuring Instruments, of which the followingisfa'speci` vticationl My present invention relatesfto an| opticaldistance-measurer provided with two-objec# tives larranged at a distancefrom each other,

`one ocular and means adapted to emit the '-rays entering through saidltwo object-- glasses throughsaid one ocular.

The purpose of my invention is to. produce'- a simple instrument givingupright with the planeof the triangleof observation, that is to s aywith the plane including the two lines of sight running from the rayreceiving ends of the instrument to the observed object, so that theobserver on using the instrument looks in the direction toward theorigin of therays which meet his eye on leaving the instrument.V

I obtain the purpose of invention by a peculiar arrangement of an evennumber' of not less than four reflecting 'surfaces in the path of therays coming `through each obj ectglass.

In order-that my invention may better bev understood I have illustratedit on the accompanying drawing in which-l Figure 1 shows the opticalelements of a distance-measurer in accordance 'with my invention. Fig. 2shows the instrument with a special form of a uniting-body provided inconnection with the instrument. jFig. 3 illustrates the function oftheimage-uniting body of Fig. 2.

In Fig. 1` I vhave shown in-v'dotted lines those optical elements whichare well known .and usual in connection withthe kind ofdistance-rneasurers; these elementsare the two pentaprisms `1 arrangedat a distance -from each other, this distance forming the basev of theinstrumentL-the two objectglassesQ .and the (ocular 4. It isfurthermorecommonl inthe construction 'of these ydistance-measurers to provide someimage` uniting body consisting of twoelementseach adapted to 'bring intothe field of View of tively. 4The numeral 12 designates the'reflectingvsurfaces of t-he right triangular elements of' the 'ocular'.an image ofan object sending rays fg-to one ofqsaid penta'prisn'is and object`-glassl7 and allowing to bring to' coincidence the two imagesof the sameobject by suit-A able adjustmentlof the instrument. Devices forefectingj such adjustment are well known and are not illustratedl in'the drawings because the same is not necessary. for a `Patented Nov. c1909.

complete understanding of the present in-V l'v entlon'.` In the drawingI have shown imagevunit, lng bodies formed of-two right triangularprisms, the reflecting surfaces of which opposite the right-angles ofthe prisms crossv each other, .as is clearlyshow-n in the drawing. Theseuniting bodies are designated on the drawing with the numeral 3.

In Fig. l I have shown, inserted in the path of the rays between eachobjectglass and the' nuage-uniting body and in proX- iinity to thelatter a further prism 5 having two `reliecting surfacesl 6, Z forming adihedron and intersecting each other inthe edge S and a furtherreflecting surfacef-'Q opposite saidv difhedron and paralleltosaid edgeS and perpendicular-to the plane of the triangle of observation. Thesurfaces of the prism 5 directed toward the entering rays and thosethrough which the'rays leave the prisms are designated l() and 11respectheimageeuniting body opposite the right- .angles of saidelements.

The arrangement of of the ocular, it is sutlicient to contemplate onlythe operation of `one half of the whole combination resulting in theformation of one of the two,1mages of thelobject which o tical elementsbe-A ing Asymmetrical W1th`re ation to the axls are to be'united bysuitableadjustment of the instrument 'inthe well known manner. -Whendoing so it is evident that the four reflecting surfacesoof such half ofthe prism combination substantially perpendicular to the plane" of thetriangle of observation compensate the :imageV reversion produced by theVobject-glass as 1far as the reversion of.

right to left and vice' versa isconcerned. The elfe'ct 'of the di-hedron6, 'Z is to compensate the .object-glass image reversion'as Vfar' as thereversion from up to down is concerned so that the construction resultsndeed `in the formation of upright-images without lateral reversion.

'Fig 2 'shows an instrument with .a peculf iar form of the image-unitingbody which is again designated with the numeral 3. This form ofimage-uniting body is distinguished from the form shown'in Fig. 1 by.this that' the crossed reflecting surfaces 12 perpendicular to the planeof the triangle of observation aresubstituted by di-hedron shapedsurfaces; in the drawing the two .dihedron forming surfaces aredesignated 14, whereas theintersecting edge is designated 15. This formof image-uniting body allows to dispense with a further prism, such asprism 5 between the pentaprisins and the iniage-uniting body. Thedi-liedroii edges 15 however being laterally displaced with relation tothe plane of contact of the two elements of the image-uniting body, anobject such as the arrow indicated in Fig. 3a of the drawing would bereproduced in the form of two parts'as indicated in Fig. 3b

of the drawing. It is however possible to shift these two parts of theimage with relation to each other by suitable adjustment of thepentaprisms 1, the necessary inclination of the surfaces of thepent-aprisins directed toward the lincoming rays being such as resultingfrom a slight rotation in oppositedirections of-said pentaprisins fromtheir normal position with parallel surfaces. -`Havng now particularlydescribed and 'ascertained lthe nature of my said invention and in whatmanner the same is to be performed, I declare that what I claim is v:`-i

' less than four reiiecting surfaces in the path `1. In `an opticaldistance-measuring iiistrument av pair of object-glasses and one ocular,the axis of the ocular substantially parallel to the plane of thetriangle of observation, means ada tedito emit the rays entering throughsaid two object -glasses .through said one ocular, so as lto forniupright images without lateral reversion, said means comprising an evennumber of not ofthe rays coming through each object glass, at least oneof said lreflecting Isurfaces in each set :of refiectors coperating withthe two object'glasses, crossing at least one reflectorA of the'otherset Without intersection, c

the crossing reflectors being arranged in parallel to the plane of thetriangle of observation, a pair of pentaprisins arranged so as to odersurfaces to the entering rays which are inclined with relation to each4other and each of same coperating with one of said obj ect-glasses, animage-uniting body including two elements in the form ofright'-triangular prisms, the reflecting surfaces of said prisms opposite theright-angles crossing each other. f 4. InV an optical distance-measurininstrument a pair of object-glasses an one ocular, the axis of theocular substantially parallel to the plane of the triangle of0bservation', a pair of pentaprisms, each cooperating with one of saidobject-glasses, an image-uniting body includin two elements in the formof right triangu ar prisms, the reflecting surfaces of said prismsopposite the rightangles crossing each other, a further prism on eachside of said unitingbody inserted in the path of the rays coming fromsaid pentaprisms and object-glasses and provided with a di-hedronsurface and a further-reflecting surface opposite said dihedron andparallel to the edge of the dihedron and substantially erpendicular t0the plane of the triangle o observation.

In` testimony whereof I have signed this 'specification in the presenceofl two subscribing witnesses.

FRIEDRICH DUBENHoRsT.

Witnesses:

WOLDEMAR HAUPT, v IIENRY IIASPER.

